- Podoconiosis is a disease of the lymph vessels in the legs and feet. It is caused by long-term barefoot exposure to irritant soils, such as those in volcanic areas. It causes severe swelling and disfigurement, as well as infection and chronic pain. It mostly affects people who live in tropical Africa, Central and South America, and India. The reasons why some people develop this disease and others do not is not well understood. Researchers want to study people with the disease and healthy volunteers in Ethiopia. They will collect skin and blood samples to study genetic and other aspects of the disease.